•Clouds the water and reduces photosynthesis,which disrupts food webs and carries bacteriaand pesticides

•It clogs and fills lakes, streams and harbors

•Decreases the efficiency of chlorine todisinfect water

Water Soluble Radioactive Isoptopes

•Can be biologically magnified in tissues andorgans

•Ionizing radiation can cause birth defects,cancer and genetic damage

Thermal Pollution

•Heat absorbed by water to cool industrial andpower plants which lowers the water qualityby lowering dissolved oxugen leels makingaquatic organisms more vulnerable to disease,parasites and toxic chemcials

Non Point Sources = pollutants that cannotbe traced to a specific site. These includelarge land areas that pollute due to runoff,subsurface flow, & deposition from theatmosphere. Agriculture produces non-pointpollution in the form of sediment, inorganicfertilizers, manure, salts dissolved in irrigationwater and pesticides.

II.

Pollution Of Streams and Lakes

•A.

Stream and River Pollution

•1.

Streams and rivers usually recover rapidlyas long as streams are

not overloaded with pollutants and flow is notreduced due to drought, damming, ordiversion for agriculture and industry

II.

Pollution Of Streams and Lakes

•Oxygen Sag Curve

= when bacteria reduces oreliminates populations of organisms with highoxygen requirements. This depends uponstream volume, flow rate, temperature, pHlevel and volume of degradable wastes. Thiscurve can also be done for thermal pollution

Fig. 19.3, p. 479

Clean Zone

Decomposition

Zone

Septic Zone

Recovery Zone

Clean Zone

Normal clean water organisms

(Trout, perch, bass,

mayfly, stonefly)

Trash fish

(carp, gar,

Leeches)

Fish absent, fungi,

Sludge worms,

bacteria

(anaerobic)

Trash fish

(carp, gar,

Leeches)

Normal clean water organisms

(Trout, perch, bass,

mayfly, stonefly)

8 ppm

Dissolved oxygen

Biological oxygen

demand

Oxygen sag

2 ppm

8 ppm

Concentration

Types of

organisms

Time of distance downstream

Direction of flow

Point of waste or

heat discharge

Reduction of Stream Pollution

•require cities to withdraw drinking waterdownstream rather than upstream, whichimproves water quality

•Water pollution laws of 1970 have increasedthe number and quality of wastewatertreatment plants which in the US and otherdeveloped countries has reduced oreliminated point source pollution

2. Most sewage in developing countries is dumpeddirectly into the ocean without treatment

* sewage and agricultural wastes

introduce

large quantities of nitrogen and phosphorus

to the water which causes algal blooms

Ocean Pollution

•Pollutants that are dumped into the ocean:

1. dredge spoils or materials full of toxic chemicalsscraped from the bottom of harbors and rivers tomaintain channels are dumped from barges andships at 110 sites in the Pacific, Atlantic and GulfCoasts

2. sewage sludge-gooey, mud like mixture of toxicchemicals, infectious agents and settled solidsremoved from wastewater at sewage treatmentplants (banned in the US since 1992)

–Tar like globs that float on the surface coatfeathers of diving and other birds and the fur ofmarine mammals, which destroys theirinsulation and buoyancy, which causes deathdue to the loss of body heat.